Liquid ejection head and method of producing same

Abstract

A method of producing a liquid ejection head comprising: a flow path forming substrate in which a space including pressure generating chambers and an ink reserving chamber is formed; a nozzle plate which is stacked on one face of the flow path forming substrate; and a vibration plate which is stacked on the other face of the flow path forming substrate is provided. The flow path forming substrate is formed by a monocrystal silicon substrate in which a plane of crystal plane orientation of ( 110 ) is the surface. When the ink reserving chamber penetrating from the one face of the substrate to the other face is formed by anisotropically etching the ( 110 ) plane of the flow path forming substrate, a ( 111 ) plane which is inclined with respect to the ( 110 ) plane is caused to appear, whereby a step portion which extends in the plate face direction of the substrate, and in which an inner wall face of the flow path forming substrate on the side of the nozzle plate is inward projected is formed on an inner wall face of the ink reserving chamber.

1. A liquid ejection head comprising:
 a flow path forming substrate having a first surface and a second surface opposite to each other and formed with a space, including a liquid reserving chamber and pressure generating chambers, the liquid reserving chamber being so formed as to communicate with each of the pressure generating chambers and to penetrate from the first surface to the second surface; 
 a nozzle plate, stacked on the first surface and provided with nozzle openings each of which is communicated with one of the pressure chambers; and 
 a sealing plate, stacked on the second surface and adapted to seal the space, 
 wherein a step is formed on an inner wall of the liquid reserving chamber, 
 wherein the inner wall is perpendicular to an ejection surface of the nozzle plate, and 
 wherein the step is formed such that a first portion of the inner wall, which is closer to the nozzle plate than the sealing plate, is projected with respect to a second portion of the inner wall, which is closer to the sealing plate than the nozzle plate. 
 
     
     
       2. The liquid ejection head according to  claim 1 , wherein the step is formed with a plane downwardly inclined toward the nozzle plate. 
     
     
       3. The liquid ejection head according to  claim 1 , wherein:
 the nozzle openings are arrayed in a first direction; and 
 the step is located at an end portion of the liquid reserving chamber in the first direction. 
 
     
     
       4. The liquid ejection head according to  claim 3 , wherein the end portion of the liquid reserving chamber is tapered in the first direction. 
     
     
       5. The liquid ejection head according to  claim 1 , wherein the flow path forming substrate is made of a monocrystal silicon substrate. 
     
     
       6. The liquid ejection head according to  claim 5 , wherein each of the first surface and the second surface is a crystal plane and the step is formed by additional crystal planes which are inclined with respect to the first surface and the second surface. 
     
     
       7. The liquid ejection head according to  claim 6 , wherein the step is formed at a boundary between a straight plane formed by one of two of the additional crystal planes that are perpendicular to the first surface and the second surface and a stepwise plane formed by the two crystal planes of the additional crystal planes. 
     
     
       8. A method of producing a liquid ejection head, comprising:
 providing a monocrystal silicon substrate having a first surface and a second surface each of which is a crystal plane; 
 etching the flow path forming substrate anisotropically so as to penetrate from the first surface to the second surface to form a space adapted to be a liquid reserving chamber reserving liquid to be supplied to pressure generating chambers each of which is formed in the flow path forming substrate and is communicated with a nozzle opening; and 
 forming a step on an inner wall of the space while etching the flow path forming substrate, 
 wherein the inner wall is perpendicular to an ejection surface of a nozzle plate stacked on the first surface, the nozzle plate containing the nozzle opening, and 
 wherein the step is formed such that a first portion of the inner wall, which is closer to the nozzle plate than a sealing plate stacked on the second surface, is projected with respect to a second portion of the inner wall, which is closer to the sealing plate than the nozzle plate. 
 
     
     
       9. The method according to  claim 8 , wherein the step is formed by additional crystal planes which are inclined with respect to the first surface and the second surface. 
     
     
       10. The method according to  claim 8 , further comprising
 placing a first etching protective film on the first surface and a second etching protective film on the second surface such that an etching boundary defined by the first etching protective film and an etching boundary defined by the second etching protective film are offset from each other in a direction parallel to the first surface and the second surface. 
 
     
     
       11. The method according to  claim 8 , comprising
 placing a first etching protective film on the first surface on which the nozzle plate is stacked and a second etching protective film on the second surface on which the sealing plate is stacked thereon such that an etching boundary defined by the first etching protective film is shifted from an etching boundary defined by the second etching protective film in a direction of a region to be the space. 
 
     
     
       12. The method according to  claim 8 , wherein:
 the nozzle openings are arrayed in a first direction; and 
 the step is located at an end portion of the liquid reserving chamber in the first direction. 
 
     
     
       13. The method according to  claim 12 , wherein the end portion of the liquid reserving chamber is tapered in the first direction. 
     
     
       14. The method according to  claim 8 , wherein the step is formed at a boundary between a straight plane formed by one of two of the additional crystal planes perpendicular to a the first surface and the second surface and a stepwise plane formed by the two crystal planes of the additional crystal planes.